Now connect marker's translation to copy's. And iterate this step to the last one.
Well.. This is kind boring job but just for the first time setup.
(I wrote a simple python script to handle this boring job. Read and download from Here!)

Okay, we have everything setup.
playback they all move in same motion( of cause we duplicated them and use reation)
click Snap on the Right body. playback again the null start moving but not in the center.
Find a facing straight neutral pose then click Zero button.
Right now the null should in the center of the face marker.

Final step:
Select copy markers and do plot.
Deactivate all constrains
Select copy null and clear it trans info

I've seem a lot people are interested in this article. Sorry for my bad skill of English writing. If you have any questions. Feel free to send me messages.